Whenever Lucas McCain had to ride out of town to conduct business of some sort in Willow Springs, he probably had no idea that about a decade earlier two Secret Service agents rode into that same town and became embroiled in a mysterious case.....
'THE WILD, WILD WEST'
"The Night Of The Sudden Plague"
Jim and Artie arrive in Willow Springs and finds a band of thieves have struck, somehow managing to paralyze everyone in the town.
From A "Wild Wild West Episode Guide"
Just thought you'd like to know. Unfortunately for me, Dr. Loveless was not involved in that case.......